feat: update solutions to lc problem: No.0268

No.0268.Missing Number

Author: maolonglong

solution/0200-0299/0268.Missing Number/README.md

@@ -113,6 +113,35 @@ class Solution {
 }
 ```
 
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int missingNumber(vector<int>& nums) {
+        int n = nums.size();
+        int res = n;
+        for (int i = 0; i < n; ++i) {
+            res ^= (i ^ nums[i]);
+        }
+        return res;
+    }
+};
+```
+
+### **Go**
+
+```go
+func missingNumber(nums []int) int {
+	n := len(nums)
+	res := n
+	for i := 0; i < n; i++ {
+		res ^= (i ^ nums[i])
+	}
+	return res
+}
+```
+
 ### **...**
 
 ```

solution/0200-0299/0268.Missing Number/README_EN.md

@@ -97,6 +97,35 @@ class Solution {
 }
 ```
 
+### **C++**
+
+```cpp
+class Solution {
+public:
+    int missingNumber(vector<int>& nums) {
+        int n = nums.size();
+        int res = n;
+        for (int i = 0; i < n; ++i) {
+            res ^= (i ^ nums[i]);
+        }
+        return res;
+    }
+};
+```
+
+### **Go**
+
+```go
+func missingNumber(nums []int) int {
+	n := len(nums)
+	res := n
+	for i := 0; i < n; i++ {
+		res ^= (i ^ nums[i])
+	}
+	return res
+}
+```
+
 ### **...**
 
 ```

solution/0200-0299/0268.Missing Number/Solution.cpp

@@ -0,0 +1,11 @@
+class Solution {
+public:
+    int missingNumber(vector<int>& nums) {
+        int n = nums.size();
+        int res = n;
+        for (int i = 0; i < n; ++i) {
+            res ^= (i ^ nums[i]);
+        }
+        return res;
+    }
+};

solution/0200-0299/0268.Missing Number/Solution.go

@@ -0,0 +1,8 @@
+func missingNumber(nums []int) int {
+	n := len(nums)
+	res := n
+	for i := 0; i < n; i++ {
+		res ^= (i ^ nums[i])
+	}
+	return res
+}

solution/0200-0299/0268.Missing Number/Solution.py

@@ -0,0 +1,6 @@
+class Solution:
+    def missingNumber(self, nums: List[int]) -> int:
+        res = len(nums)
+        for i, v in enumerate(nums):
+            res ^= (i ^ v)
+        return res